Reactive oxygen species (ROS) are cellular byproducts formed by the metabolism of oxygen, are responsible for cell oxidative damages, and can be the cause of cellular injury, cellular dysfunction, and cell death (apoptosis). The effects of ROS on cell metabolism have been well documented. Accumulation of ROS in tissue may cause oxidative injury, and thus it may be desirable to reduce the amounts of ROS in tissues. It is desirable to monitor ROS generation in cells to determine whether ROS are involved in diseases including cardiovascular, inflammatory, and infectious diseases. Cells normally are capable of preventing oxidative damage from ROS with enzymes, such as superoxide dismutase or catalase. Other compounds also are useful in preventing such damage, including antioxidants such as vitamins, uric acid, and glutathione. Such compounds, (e.g., antioxidants), may play an important role in scavenging free radicals and protecting the host organism from pathogens.
Although many methods have been developed to measure ROS quantities in tissue, there are few methods that measure intracellular ROS concentrations in real time. The ability to measure ROS quantities is important, in that ROS concentrations may change, e.g., increase or decrease, over time.
Accordingly, there is a continuing interest in developing and administering effective antioxidant compositions to prevent ROS damage. There are few methods, however, that are capable of measuring the effects of compositions on ROS production in real time. It therefore would be desirable to develop methods that can measure the effects of components on intracellular ROS production.